Hordini wrote:
Marine crunches aren't really what most people think of when they think of crunches. It's more like a half situp, really. It's supposed to demonstrate core/abdominal strength, but in my experience it tends to work the hip flexors as much as the abs, if not more.
I've thought about it a little more and they make sense now. The exercise specifically targets the abdominal wall, which aids in breathing and protects internal organs.